Keywords: Monism, Dualism, Ius cogens, Customary norms, Non-refoulement.
The essay deals with the issue of relationships between the Constitution and the customary norms of international order. After reconstructing the fundamental terms of the dialectic between monism and dualism, the work analyzes the meaning of the fundamental principle of opening up our constitutional dimension to international customary norms, of which it takes into particular account the norms of ius cogens. These are at the crossroads of multiple theoretical
questions, which emerge with reference to the traditional classification of the sources of law in the system, among which the tendency to find in the contents of the source the tool to define its degree and legal regime deserves particular attention.